diff --git a/mach/compare b/mach/compare
index 32b8be1be..fc54003f9 100755
--- a/mach/compare
+++ b/mach/compare
@@ -1,2 +1,7 @@
+case $# in
+1)	DEST="$1" ;;
+2)	DEST="$2" ;;
+*)	echo $0 [source] destination ;;
+esac
 MACH=`(cd .. ; basename \`pwd\`)`
-cmp $1 ../../../lib/${MACH}/$1
+cmp "$1" ../../../lib/${MACH}/$DEST